Add system CPU metrics to metrics-v3 (#19560)

endpoint: /minio/metrics/v3/system/cpu

metrics:
- minio_system_cpu_avg_idle
- minio_system_cpu_avg_iowait
- minio_system_cpu_load
- minio_system_cpu_load_perc
- minio_system_cpu_nice
- minio_system_cpu_steal
- minio_system_cpu_system
- minio_system_cpu_user

cmd/metrics-v3.go

@@ -36,6 +36,7 @@ const (
 	systemNetworkInternodeCollectorPath collectorPath = "/system/network/internode"
 	systemDriveCollectorPath            collectorPath = "/system/drive"
 	systemMemoryCollectorPath           collectorPath = "/system/memory"
+	systemCPUCollectorPath              collectorPath = "/system/cpu"
 	systemProcessCollectorPath          collectorPath = "/system/process"
 	systemGoCollectorPath               collectorPath = "/system/go"
 
@@ -128,6 +129,20 @@ func newMetricGroups(r *prometheus.Registry) *metricsV3Collection {
 		loadMemoryMetrics,
 	)
 
+	systemCPUMG := NewMetricsGroup(systemCPUCollectorPath,
+		[]MetricDescriptor{
+			sysCPUAvgIdleMD,
+			sysCPUAvgIOWaitMD,
+			sysCPULoadMD,
+			sysCPULoadPercMD,
+			sysCPUNiceMD,
+			sysCPUStealMD,
+			sysCPUSystemMD,
+			sysCPUUserMD,
+		},
+		loadCPUMetrics,
+	)
+
 	systemDriveMG := NewMetricsGroup(systemDriveCollectorPath,
 		[]MetricDescriptor{
 			driveUsedBytesMD,
@@ -235,6 +250,7 @@ func newMetricGroups(r *prometheus.Registry) *metricsV3Collection {
 		systemNetworkInternodeMG,
 		systemDriveMG,
 		systemMemoryMG,
+		systemCPUMG,
 
 		clusterHealthMG,
 		clusterUsageObjectsMG,